ref: d388629dae7e6ab368015e3fc5c8c12c0e20fae1 dir: /sys/src/libc/riscv64/argv0.s/
GLOBL argv0(SB), $XLEN GLOBL _tos(SB), $XLEN GLOBL _privates(SB), $XLEN GLOBL _nprivates(SB), $XLEN